For high track density recording, tighter reader and writer track width control is the key ingredient for obtaining high yield. How to continue improving the writer track width by using a pole trim process together with a narrow pole width is a challenging task. The basic principle to having tighter pole width control is to have a thinner pole resist process so that photo CD (critical dimension) control can be further improved. Reducing the amount of pole material consumed during the pole trim process, without impacting performance, is the key factor associated with using a thinner pole resist.
There have been several proposals to utilize a plated S2 (writer lower shield), a plated write gap, and a plated P2 (top pole) in a single photo process thereby minimizing the extent of pole trim consumption. However, with this scheme the throat height definition is rather poor so this type of design creates magnetic flux leakage between pole and shield. So poor overwrite is a consequence of this type of design.
The present invention discloses an improved scheme that applies to both stitched writers and planar writers.
A routine search of the prior art was performed with the following references of interest being found:
In U.S. Pat. No. 6,594,112, Crue et al. disclose NiPd plating to more accurately define throat height. Alumina is used as the insulating material. In U.S. Pat. No. 6,621,659, Shukh et al. show alumina in the recess to define throat height.